The musings of a bearded earthling

Category Archives: Antarctica

A huge Antarctic ice shelf is on the brink of collapse with just a sliver of ice holding it in place, the latest victim of global warming that is altering maps of the frozen continent.

‘We’ve come to the Wilkins Ice Shelf to see its final death throes,’ David Vaughan, a glaciologist at the British Antarctic Survey (BAS), told Reuters after the first — and probably last — plane landed near the narrowest part of the ice.

The flat-topped shelf has an area of thousands of square kilometers, jutting 20 meters (65 ft) out of the sea off the Antarctic Peninsula.

But it is held together only by an ever-thinning 40-km (25-mile) strip of ice that has eroded to an hour-glass shape just 500 meters wide at its narrowest.

In 1950, the strip was almost 100 km wide.

‘It really could go at any minute,’ Vaughan said on slushy snow in bright sunshine beside a red Twin Otter plane that landed on skis. He added that the ice bridge could linger weeks or months.

I suppose it is a good sign that I’m having a hard time keeping up with all of the recent media coverage of climate change. I would like to point out though that while the coverage is now consistent via the web I’m not seeing it nearly as much on the television. I don’t watch much but when I do flip on the TV and CNN I’m much more likely to see discussion of stupid, irrelevant celebrity gossip than I am discussion of climate change. That’s just plain fucked up. Until the corporate media stop the daily bullshit coverage of Anna Nicole’s baby’s daddy and replace it with daily discussion of peak oil, climate change, and sustainable development they are as much a part of the problem as they have always been.

The impact of climate change has been a major source of disputeBillions of people face shortages of food and water and increased risk of flooding, experts at a major climate change conference have warned.

BRUSSELS, Belgium (AP) — While governments grapple with the politics of global warming, some of the world’s greatest treasures already are being damaged and threatened with destruction.

Conservationists have drawn up priorities for action to salvage some of nature’s wonders that are feeling the heat of climate change — from the Himalayan glaciers to the Amazon rain forests and the unique ecosystem of the Mexican desert.

Many of the regions at risk were singled out in a report by the Intergovernmental Panel on Climate Change, an authoritative body of 2,500 scientists. The report is undergoing governmental review at a five-day conference in Brussels.

On Thursday, diplomats and scientists were negotiating the text of a 21-page summary of the full 1,572-page scientific report. It projects specific consequences for each degree of rising global temperatures, which the IPCC agrees is largely caused by human activity.

On the sidelines of the conference, the World Wildlife Fund for Nature issued a list of 10 regions suffering irreversible damage from climate change. The group also listed where it has projects to limit further damage or help people adapt to new conditions.

“What we are talking about are the faces of the impacts of climate change,” said Lara Hansen, WWF’s chief scientist on climate issues.

The WWF is among the largest of many nongovernment organizations to take up the challenge of climate change.

The Nature Conservancy, based in Arlington, Virginia, is another. It has projects to protect coral reefs off Florida, in the coral triangle of Indonesia and in Papua New Guinea. It also is trying to preserve native alpine meadows in China and conserve vegetation in California’s Sierra Nevada mountains.

Though climate change has been discussed for decades, Hansen said the effects were now becoming visible. “It’s only in the past decade that we can go outside and see for ourselves what’s happening,” she told The Associated Press.

Some damage is reversible, Hansen said. Although melted glaciers cannot be restored, some coral reefs can recover.

But as natural landmarks deteriorate, she said more attention will have to be paid to adapting to change, not only trying to prevent it, and not enough experts are being trained to help people acclimatize.

Changing climate will mean increasing drought in the southwestern United States, where water already is in short supply, according to a new study.

“The bottom line message for the average person and also for the states and federal government is that they’d better start planning for a Southwest region in which the water resources are increasingly stretched,” said Richard Seager of Columbia University’s Lamont Doherty Earth Observatory.

Seager is lead author of the study published online Thursday by the journal Science.

Researchers studied 19 computer models of the climate, using data dating back to 1860 and projecting into the future. The same models were used in preparing the reports of the Intergovernmental Panel on Climate Change.

The consensus of the models was that climate in the southwestern United States and parts of northern Mexico began a transition to drier conditions late in the 20th century and is continuing the trend in this century, as climate change alters the movement of storms and moisture in the atmosphere.

The reduction in rainfall could reach levels of the 1930s Dust Bowl that ranged throughout the Midwestern United States, Seager said in a telephone interview.

“Our study gives the first reliable estimates of how perennial ice replenishment varies each year at the end of the summer.

“The amount of first-year ice that survives the summer directly influences how thick the ice cover will be at the start of the next melt season.”

The team observed that only 4.0 percent, about 2.5 million square kilometers (965,000 square miles) of thin ice survived the 2005 summer melt to replenish the perennial cover.

It was the weakest ice cover since 2000, and so there was 14 percent less permanent ice cover in January 2006 than in the corresponding period the year before.

“The winters and summers before fall 2005 were unusually warm,” Kwok said. “The low replenishment seen in 2005 is potentially a cumulative effect of these trends.

“If the correlations between replenishment area and numbers of freezing and melting temperature days hold long-term, it is expected the perennial ice coverage will continue to decline.”

Records dating back to 1958 have shown a gradual warming of Arctic temperatures which speeded up in the 1980s.

“Our study suggests that on average the area of seasonal ice that survives the summer may no longer be large enough to sustain a stable, perennial ice cover, especially in the face of accelerating climate warming and Arctic sea ice thinning,” Kwok added.

A Texas-sized piece of the Antarctic ice sheet is thinning, possibly due to global warming, and could cause the world’s oceans to rise significantly, polar ice experts said on Wednesday.

They said “surprisingly rapid changes” were occurring in Antarctica’s Amundsen Sea Embayment, which faces the southern Pacific Ocean, but that more study was needed to know how fast it was melting and how much it could cause the sea level to rise.

The warning came in a joint statement issued at the end of a conference of U.S. and European polar ice experts at the University of Texas in Austin.

The scientists blamed the melting ice on changing winds around Antarctica that they said were causing warmer waters to flow beneath ice shelves.

The wind change, they said, appeared to be the result of several factors, including global warming, ozone depletion in the atmosphere and natural variability.

The thinning in the two-mile-(3.2-km)- thick ice shelf is being observed mostly from satellites, but it is not known how much ice has been lost because data is difficult to obtain on the remote ice shelves, they said.

Study is focusing on the Amundsen Sea Embayment because it has been melting quickly and holds enough water to raise world sea levels six meters, or close to 20 feet, the scientists said.

Some of the largest glaciers in Antarctica and Greenland are moving in unusual ways and are losing increased amounts of ice to the sea, researchers said yesterday.

—Complicating the situation for those studying Antarctica, some parts of the continent are gaining ice depth through snowfall while temperatures on the tip of the Antarctic peninsula, the continent’s closest point to South America, are rising faster than almost anywhere else on the planet. The surprisingly fast-moving glaciers are largely on the West Antarctic ice sheet.

Wingham, of University College London, and Andrew Shepherd of the University of Edinburgh said satellite radar readings show that overall, each year the ice loss from Greenland and Antarctica amounts to about 10 percent of the rise in the global sea level, which totals about one-tenth of an inch per year. The net loss of Antarctic ice is estimated to be 25 billion metric tons a year, despite the growth of the ice sheet in East Antarctica.

Because such a large percentage of the world’s ice is found in those two locations, scientists are carefully watching for signs of increased ice loss. If that process accelerates, researchers say, it could result in a substantial, and highly disruptive, increase in sea levels worldwide.

In Greenland, glaciers appear to be moving more quickly to sea because melting ice has allowed the sheet to slide more easily over the rock and dirt below. In Antarctica, the loss is believed to be associated with the breaking off into seawater of ice deep under the ice sheet with little-understood internal dynamics that put increased pressure on the massive ice streams.

The impact of global warming on the vast Southern Ocean around Antarctica is starting to pose a threat to ocean currents that distribute heat around the world, Australian scientists say, citing new deep-water data.

Melting ice-sheets and glaciers in Antarctica are releasing fresh water, interfering with the formation of dense “bottom water,” which sinks 4-5 kilometers to the ocean floor and helps drive the world’s ocean circulation system.

I’m definitely seeing a pattern with the reporting on climate change stories. Seems that with every single story on every new report it is always we underestimated the effects or this particular effect is happening much sooner than we thought it would. The BBC reports that Sea level rise ‘under-estimated’:

Current sea level rise projections could be under-estimating the impact of human-induced climate change on the world’s oceans, scientists suggest.

By plotting global mean surface temperatures against sea level rise, the team found that levels could rise by 59% more than current forecasts.

The researchers say the possibility of greater increases needs be taken into account when planning coastal defences.

The findings have been published in the online edition of the journal Science.

The team from Germany and the US found that for the timescale relevant to human-induced climate change, the observed rate of sea level rise through the 20th Century held a strong correlation with the rate of warming.

When applied to the possible scenarios outlined by the Intergovernmental Panel on Climate Change (IPCC), the researchers found that in 2100 sea levels would be 0.5-1.4m above 1990 levels.

This projection is much greater than the 9-88cm forecast made by the IPCC itself in its Third Assessment Report, published in 2001.

…

He writes in Science Express: “Understanding global sea level changes is a difficult physical problem, as a number of complex mechanisms with different timescales play a role.”

These include:

* thermal expansion of water through heat absorption* water entering the oceans from glaciers and ice sheets* increased ice flows after the removal of buttressing ice shelves

Professor Rahmstorf said he decided to use observational data because computer models of climate significantly under-estimated the sea level rise that had already occurred.

“The fact that we get such differences using different methods shows how uncertain our sea level forecasts still are,” he said.

Greenland’s glaciers have been sliding faster towards the sea

He added that the main uncertainty was the response of large ice sheets in Greenland and Antarctica to rising temperatures, which was difficult to predict.